Peck Drilling Calculator
Figure out how many pecks a deep hole needs, and how deep the last one actually goes, before you write the G83 cycle.
Why peck instead of drilling straight through
Past roughly 3× the drill's diameter in depth, chips no longer clear the flutes on their own — they pack into the flute, re-cut, generate excess heat, and can pack tightly enough to snap the drill. Peck drilling retracts the drill fully or partially at set intervals to clear the flute and let coolant back in, trading cycle time for a drill that survives the hole.
Picking a peck depth multiplier
A peck depth of roughly 1× the drill diameter is a common general-purpose starting point — go shorter (0.5–0.75×) in tough, stringy, or gummy materials that pack chips easily, and you can often go longer (1.5–3×) in free-machining materials like aluminum or brass that break chips more cleanly on their own.
Full retract vs. chip-break pecking
This calculator assumes a full-retract peck cycle (like G83), where the drill backs all the way out of the hole every peck to clear chips completely. A chip-break cycle (like G73) only backs off a small amount each peck rather than fully retracting, trading some chip-clearing certainty for a faster cycle — useful once you already know a material breaks chips cleanly and full retraction is overkill.